An increasing number of applications have been developed for supporting network communities. The authors have developed Community Organizer, which supports people in forming new network communities by providing places where people sharing interests and concerns can meet and communicate. The authors are also developing a platform named Shine to reduce the tasks needed to implement a variety of network community support systems such as Community Organizer. Shine has a multi-agent architecture because it is effective for network community support systems that have to adapt to dynamic changes in community organizations. This paper explains both Community Organizer and Shine, and then gives a description of building Community Organizer on top of Shine.